Synthesis 2019; 51(19): 3617-3624
DOI: 10.1055/s-0039-1690104
paper
© Georg Thieme Verlag Stuttgart · New York

1-Nicotinoylbenzotriazole: A Convenient Tool for Site-Selective Protection of 5,7-Dihydroxycoumarins

Authors

  • Ramil F. Fatykhov

    a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   Email: i.a.khalymbadzha@urfu.ru
  • Igor A. Khalymbadzha

    a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   Email: i.a.khalymbadzha@urfu.ru
    b   Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Kovalevskoy 22, 620219 Ekaterinburg, Russian Federation
  • Oleg N. Chupakhin

    a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   Email: i.a.khalymbadzha@urfu.ru
    b   Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Kovalevskoy 22, 620219 Ekaterinburg, Russian Federation
  • Valery N. Charushin

    a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   Email: i.a.khalymbadzha@urfu.ru
    b   Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Kovalevskoy 22, 620219 Ekaterinburg, Russian Federation
  • Anna K. Inyutina

    a   Department of Organic and Biomolecular Chemistry, Ural Federal University, Mira 19, 620002 Ekaterinburg, Russian Federation   Email: i.a.khalymbadzha@urfu.ru
  • Pavel A. Slepukhin

    b   Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Kovalevskoy 22, 620219 Ekaterinburg, Russian Federation
  • Victor G. Kartsev

    c   InterBioScreen Ltd., Institutsky Prospect 7a, 142432 Chernogolovka, Russian Federation

We are grateful to the Russian Science Foundation (project #18-73-00163, synthesis of compounds 611) and the Ministry of Education and Science of the Russian Federation (project 4.6351.2017/8.9, synthesis of compounds 12 and 13).
Further Information

Publication History

Received: 13 March 2019

Accepted after revision: 07 June 2019

Publication Date:
26 June 2019 (online)


Graphical Abstract

Preview

Abstract

1-Nicotinoylbenzotriazole (NicBt) was uncovered as an efficient protecting agent for the site-selective acylation of resorcinol-type phenolic groups with almost equal reactivity. The use of NicBt allows selective protection of the 7-OH group in 5,7-dihydroxycoumarins in one simple scalable step, while combination of the nicotinoylation with tosylation–denicotinoylation or silylation–denicotinoylation yields 5-OH-protected 5,7-dihydroxycoumarins. Furthermore, nicotinoylated 5,7-dihydroxycoumarins proved useful in a gram-scale three-step preparation of a 2,2-dimethylpyrano[2,3-f]coumarin, a key intermediate for the synthesis of calanolide A, an HIV reverse transcriptase and Mycobacterium tuberculosis inhibitor, and its active analogues.

Supporting Information